Quoted:
Are the AAR/C uppers available, and will they work with an unmodified M16 lower? Are there limitations on the types of handguards/rails/stocks that fit?
While AAR uppers are currently available, AAR/C uppers configured for semi-auto are still a few months out. The select-fire configuration does work with unmodified M16 lower receivers as do all models of the Shrike 5.56 family of weapons. The factory sear in the unmodified lower is timed and tripped via a proprietary mechanism and anti-bounce weights are integral to the recoiling mass.
Handguards are limited to the models that we supply as they form an integral part of the quick-change barrel system and also house the operating rod assembly.
The AAR/C operates with the stock folded or open. We also have a telescoping design similar to an MP-5A3 but with adjustable length of pull to permit the operator/end-user to compensate for armor, gear, etc. Most AR/M16 type of stocks will work also, with the exception of those that form a triangular cheek weld, as they interfere with the side mounted charging handle when telescoped inward.